Non-invasive and continuous monitoring of cerebral blood flow as a parameter for neurological deterioration in acute brain injury

Abstract

Background Monitoring the cerebral blood flow (CBF) is crucial when caring for patients in neurological intensive care units (NICU). Changes in CBF, either due to hypo- or hyperperfusion, have been associated with neurological deterioration. By using a non-invasive continuous CBF monitor, we aimed to assess whether cerebral flow index (CFI) fluctuations could correlate with neurological deterioration. Methods We prospectively collected data from patients with acute brain injury (subarachnoid hemorrhage [SAH], Moyamoya disease [MMD], and ischemic stroke), who were at a high risk for CBF disturbance between May 2017 and June 2019. Non-invasive CBF measurements were performed in the bilateral prefrontal cortex using a c-FLOW device. Continuous CBF was assessed using CFI. The delta value and percent change in the CFI were compared between patients with and without neurological deterioration. Results A total of 45 patients (mean age, 51.6 years; male, 48.9%) were included in our analysis (SAH, 13; MMD, 17; ischemic stroke,15). The mean monitoring duration was approximately 52 hours. Nine patients (20.0%) had neurologic worsening during c-FLOW monitoring in NICU. The delta value (median, 10.4; interquartile range [IQR], 3.9–14.3 vs. median, 3.4; IQR, 2.5–5.6; P=0.008) and percent change in CFI (28.5% vs. 9.0%, P<0.001) was significantly higher in groups with neurological deterioration. In two patients with neurological deterioration, no CFI change was observed because aggravation of cerebral perfusion occurred outside the area of CFI monitoring. Conclusion Continuous non-invasive CBF monitoring with c-FLOW may be useful for patients with acute brain injury at high risk for CBF alterations.

Keywords

• acute brain injury
• cerebral blood flow
• cerebral flow index
• monitoring
• neurologic deterioration